## https://yukicoder.me/problems/no/1861


def main():
    N, K = map(int, input().split())
    A = list(map(int ,input().split()))

    # そもそも存在する？
    dp = [[0] * (K + 1) for _ in range(N + 1)]
    dp[0][0] = 1
    for i in range(N):
        a = A[i]        
        for x in range(K + 1):
            if x + a <= K:
                dp[i + 1][x + a] |= dp[i][x]
            dp[i + 1][x] |= dp[i][x]
    
    if dp[-1][K] == 0:
        print(-1)
        return
    
    answer = 0
    dp0 = [0] * (K + 1)
    dp0[0] = 1
    for i in reversed(range(N)):
        is_ok = True
        for k in range(K + 1):
            k0 = K - k
            if dp0[k] == 1 and dp[i][k0] == 1:
                is_ok = False

        if is_ok:
            answer += 1

        a = A[i]
        new_dp = dp0.copy()
        for x in range(K + 1):
            if x + a <= K:
                new_dp[x + a] |= dp0[x]
        dp0 = new_dp
    print(answer)

                        


    






if __name__ == "__main__":
    main()